The real legacy of this year’s mayoral campaign isn’t the triumph of Marty Walsh, the passionate, hard-working son of the city; nor is it the downfall of John Connolly. The race to replace Mayor Tom Menino resonates because of how it unfolded, and what it portends for the way state and local campaigns operate in the super PAC era.

The first open Boston mayor’s contest in a generation was the race that broke the state’s campaign finance system. A campaign that began with direct appeals to voters in neighborhood auditoriums finished as a flood of uncontrolled, untraceable outside money. And, absent rapid reform on Beacon Hill, it’s a preview of things to come.

Money and politics have always traveled together, but the Supreme Court’s 2010 Citizens United decision drastically altered the relationship between the two. Citizens United removed spending and fundraising caps on political action committees. Wealthy individuals, corporations, and labor unions are now free to pour as much money as they want into political contests, as long as their PACs are not directly cooperating with campaigns.

The outside super PACs that Citizens United unleashed initially dove into presidential politics. However, moneyed interests on both sides of the political spectrum are finding that there’s far more impact to be had in lower-money state and local races. Democratic- and labor-aligned super PACs just poured tens of millions of dollars into legislative races in New Jersey, while the billionaire Koch brothers have taken to playing small-town politics in Iowa. Education activists outspent the field of candidates in Los Angeles’s school committee races this spring 5 to 1. Groups across the political spectrum have acquired a sudden taste for big money. They’re remaking politics, and nowhere is that more apparent more than in Boston.

Stand for Children brought Boston’s mayoral race to a standstill in August, when the education reform group announced plans to spend at least $500,000 promoting Connolly’s candidacy. A furor erupted, and Connolly swore off all spending by sympathetic outside groups like Stand for Children. Having bowed to pressure from other mayoral candidates to refute Stand’s money, Connolly asked his opponents to do the same. Walsh refused. At the time, Walsh was the beneficiary of over $230,000 in outside spending; that’s less than one-10th the total sum that pro-Walsh outsiders would eventually dump into the race.

The outrage over unfettered spending in the Boston mayoral campaign came before, not after, the real money entered the race. Outside PACs have reported spending $2.5 million on field operations, mailers, and media advertisements promoting Walsh’s candidacy. Democrats for Education Reform jumped into the campaign late, and spent over $1.3 million on Connolly’s behalf.

The saturation of outside money in Boston’s mayoral race has been unprecedented. On a per-capita basis, outside labor groups and super PACs have spent twice as much in Boston’s mayoral race as they did in Los Angeles, and six times what they’ve spent in New York’s mayoral contest. The $4 million outside PACs spent in Boston is $1 million more than the combined campaign spending of mayoral hopefuls Felix Arroyo, John Barros, Rob Consalvo, Charlotte Golar Richie, Mike Ross and Bill Walczak. Since they began spending in earnest, outside PACs have nearly matched Walsh and Connolly’s combined spending, dollar for dollar.

Walsh’s name often pops up because the mayor-elect benefited from the vast majority of the outside money spent in the mayoral race. The issue isn’t Walsh, though. The practice of electioneering in Massachusetts is suddenly far ahead of any effort to regulate it.

Citizens United has created a perverse two-tier campaign finance system locally, where the candidates themselves are subject to strict fundraising and disclosure requirements, but outside groups may accept unlimited buckets of money, spend it freely, and obscure the source of their funds. Two super PACs, American Working Families and One Boston, combined to dump $1.6 million into pro-Walsh television commercials; they won’t have to disclose their donors until January, and when they do, there’s no guarantee those donors won’t be hiding behind a shell corporation.

A candidate’s calculus used to revolve around raising money and counting votes; now, it becomes about how to overcome a potential mountain of super PAC money. Races on Beacon Hill aren’t any more immune to this shift than Boston’s City Hall was. With an open race for governor looming, Beacon Hill can’t override the Supreme Court and stanch the flow of outside money into local politics. But at the very least, lawmakers can act to bring some meaningful transparency to the process.

Paul McMorrow is an associate editor at Commonwealth Magazine. His column appears regularly in the Globe.

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